I've recently purchased a 2001 400EX, it's pretty much been rode hard and put up wet, I gave $800.00 for it. My intentions are to go through the bike and pt it back in really good shape cosmetically and mechanically: plastics, nerf-bars, front bumper. As far as the engine is concerned I'm wanting to rebuild it, possibly put a bore kit in, cam, etc. I'm looking for ideas like best combinations to maximize performance, and also from a dollar value standpoint. Thanks in advance for information.
A aftermarket pipe and filter are the easiest way to increase the power. Remember all modifications compliment each other. So some mods you have to do other things to actually make gains from it. The pipe and filter are simple easy cheap power.